It is a common practice to back up data in a computer environment. When the data is backed up to a backup medium, such as a tape drive or a hard drive, additional information, herein referred to as the index, can also be delivered from the computer system which is backing up its data. The index provides information about the data that is being backed up, such as how the backup data is organized. The index is often received in a random order and the received index typically needs to be reorganized. For a large number of indexes, the organization of the index at the end of the backup, can take a very long time and consume high system resources. It would be desirable to be able to organize the index in a way that avoids the extremely long time periods typically required to rebuild the index.